Quantum Optics with Polariton Condensates

在微腔结构中产生极化子的玻色凝聚体现在是相当常见的。此外，我们现在拥有的结构，与它们的热化时间相比，具有非常长的极化子寿命，所以我们可以用这些粒子的平衡凝聚体做实验。根据我们制造长寿命极化凝聚体的能力，该项目有三个主要目标。首先，我们计划使用极化凝聚体来产生增强的双光子吸收。原则上，这种增强可以是如此之大，以至于即使对于两个单光子的集合，双光子吸收过程也变得确定。这将对量子光学领域产生立竿见影的影响。第二个主要目标是绘制平衡极化子凝聚体的相图，它是密度和温度的函数，重点是凝聚体光谱函数的变化，这是我们可以立即观察到的。此外，我们计划创建相交的弹道极化子光束，这将使我们能够进行许多极化子-极化子散射研究。玻色凝聚是一种普遍存在的效应，在这种效应中，许多粒子自发地组织起来，作为一个单一的波。最广为人知的例子是超低温下的原子气体，但这种效应也出现在其他系统中。近年来，它被证明是在中等温度(几十开尔文)下发生的，被称为“极化子”的粒子，本质上是被赋予原子性质的光子，即质量和弱相互作用，通过特殊设计的光学系统。该项目的一个主要目标是使用玻色凝聚态的极化子来操纵红外光子的传输。如果这一目标成功，我们将拥有一个系统，其中通过系统的一个光子将不受影响，但同时通过的两个光子将被吸收。这种操纵单光子的能力可以用于许多量子光通信方案中。该项目将为从事该项目的研究生进行尖端光学研究提供巨大的经验。

Creating Bose condensates of polaritons in microcavity structures is now fairly routine. In addition, we now have structures which have very long polariton lifetime compared to their thermalization time, so that we can do experiments with equilibrated condensates of these particles. This project has three primary goals based on our ability to make long-lifetime polariton condensates. First, we plan to use a polariton condensate to create enhanced two-photon absorption. In principle, this enhancement can be so much that the two-photon absorption process becomes deterministic even for sets of two single photons. This would have immediate impact in the area of quantum optics. The second main goal is to map the phase diagram of an equilibrium polariton condensate as a function of density and temperature, with emphasis on the changes of the spectral function of the condensate, which is immediately observable to us. In addition, we plan to create intersecting beams of ballistic polaritons, which would allow us to do many polariton-polariton scattering studies.Bose condensation is a ubiquitous effect in which many particles spontaneously organize to act collectively as a single wave. The most well known example of this is a gas of atoms at ultra-low temperatures, but the effect occurs in other systems as well. In recent years, it has been shown to occur at moderate temperatures (tens of Kelvin) with particles called "polaritons", which are essentially photons that have been given atom-like properties, namely mass and weak interactions, by means of a specially designed optical system. A main goal of this project is to use a Bose condensate of polaritons to manipulate the transmission of infrared photons. If this goal succeeds, we will have a system in which one photon passing through the system will be unaffected, but two photons passing through together will be absorbed. This ability to manipulate single photons can be used in a number of schemes of quantum optical communications. The project will be tremendous experience for graduate students working on the project to do cutting edge optics research.